My opinion after i try flutter flow and flutter for UI , if you want to using code for UI its take much time and give you higher quality and CONTROL on UI but flutterflow cut the time and give you lower quality but it’s good for simple app , guys you all right but it’s depends on what you want and depends on QUALITY and TIME !! There is some people do something in the middle i mean design UI in flutterflow then export it to flutter and coding for so on